In another thick-based pan blend cornflour, cream of tartar and 1 cup cold water until smooth. Boil remaining 2 cups water and stir into cornflour mixture then place over low heat. Stir constantly until mixture thickens and bubbles. Use a balloon whisk if lumps form. Pour hot syrup gradually into cornflour mixture stirring constantly. Bring to a boil then gently boil for 1 1/4 hours. Stir occasionally with a wooden spoon and cook until mixture is a pale golden colour. Stirring is essential. Stir in rose water to taste and a few drops of red food colouring to tinge it pale pink.

Blend in nuts if used and remove from heat. Pour into an oiled 23 cm (9 inch) square cake tin and leave for 12 hours to set. Combine confectioners' sugar and the 1/4 cup cornflour in a flat dish. Cut Turkish Delight into squares with an oiled knife and toss in sugar mixture. Store in a sealed container with remaining sugar mixture sprinkled between layers.